Reason And Timing For Conversion To Sternotomy In Robotic-assisted Coronary Artery Bypass Grafting And Patient Outcomes
Nickolas Christidis, Stephanie Fox, Stuart Swinamer, Rodrigo Bagur, Kumar Sridher, Shahar Lavi, Ivan Iglesius, Daniel Bainbridge, Philip Jones, Christopher Harle, Michael Chu, Patrick Teefy, Bob Kiaii.
London Health Sciences Center, London, ON, Canada.
Objective: Robotically-assisted coronary artery bypass grafting (RA-CABG) is an attractive revascularization strategy as it permits convenient harvesting of the left internal thoracic artery (LITA) and minimally invasive revascularization of the left anterior descending (LAD) coronary artery. However, conversion to sternotomy remains a complication for RA-CABG procedures. The purpose of this study is to identify the primary reasons for conversion from RA-CABG to sternotomy in patients who had undergone preoperative computed tomography (CT) scan and evaluate the in-hospital outcomes in such patients. Methods: Prospectively collected data from February 2004 to April 2017 was reviewed for 73 patients (57 male; mean age 63.9) who required conversion to sternotomy during a RA-CABG procedure with planned endoscopic LITA harvest and anastomosis to the LAD on the beating heart. Results: The rate of conversion from RA-CABG to sternotomy was 14.4%, in patients who had preoperative CT thorax. Endoscopic LITA harvesting was successful in 68.5% of converted patients. Conversions occurred either during attempted endoscopic LITA harvest (31.5%), during endoscopic isolation of the LAD (41.1%), during manual isolation and anastomosis of the LAD (19.2%), or after anastomosis due to an unsatisfactory flow measurement on intraoperative angiography (8.2%). The reasons for each category of conversions are presented in Table 1. The median intensive care unit length of stay was 1 day (range, 0 - 20) and median hospital length of stay was 5 days (range, 3 - 43). In-hospital complications included new atrial fibrillation (16.4%), need for blood transfusion (20.6%), mediastinitis (4.1%), postoperative myocardial infarction (2.7%), exploration for bleeding (2.7%), and one in-hospital mortality. Conclusions: The reasons for conversion were primarily due to anatomic factors that create difficulties for endoscopic LITA harvesting (e.g. inadequate intrathoracic cavity space) and identification of the LAD for anastomosis (e.g. intramyocardial or small LAD). This knowledge can be used to develop further empirical anatomic selection criteria with the goal of decreasing conversion rate to sternotomy further during RA-CABG. Patients who required conversion to sternotomy from RA-CABG demonstrated good outcomes and low complication rates.
| Reason for Conversion | Off-pump surgery, n = 64 (87.7%) | On-pump surgery with CPB, n = 9 (12.3%) |
| During attempted endoscopic LITA harvest, n = 23 (31.5%) | ||
| Single lung ventilation not tolerated | 7 | |
| Pleural adhesions | 5 | |
| Inadequate intrathoracic cavity space | 4 | 1 |
| Large heart | 1 | |
| LITA bleed | 2 | |
| Hypotension | 1 | 1 |
| Ventricular fibrillation | 1 | |
| During endoscopic identification of the LAD, n = 30 (41.1%) | ||
| LITA plaque | 2 | |
| Buried LAD† | 22 | 1 |
| Small LAD | 3 | |
| Diseased ramus intermedius artery | 1 | |
| Multivessel disease (four grafts) | 1 | |
| During direct identification or anastomosis of the LAD, n = 14 (19.2%) | ||
| Buried LAD | 8 | |
| Small LAD | 1 | |
| Right ventricle tear during anastomosis | 1 | |
| Ventricular tachycardia | 1 | |
| Ventricular fibrillation | 1 | 1 |
| Angiography equipment malfunction | 1 | |
| After anastomosis following intraoperative angiography, n = 6 (8.2%) | ||
| Unsatisfactory flow measurement | 5 | 1 (VF) |
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